tsbob

@interface NSDictionary(JSONCategories)
+(NSDictionary*)dictionaryWithContentsOfJSONURLString:
  (NSString*)urlAddress;
-(NSData*)toJSON;
@end
 
@implementation NSDictionary(JSONCategories)
+(NSDictionary*)dictionaryWithContentsOfJSONURLString:
  (NSString*)urlAddress
{

tsbob

NSString* aStr = [[NSString alloc] initWithData:aData encoding:NSASCIIStringEncoding];
NSData* aData = [aStr dataUsingEncoding: NSASCIIStringEncoding];

//If the data is null-terminated, you should instead use -stringWithUTF8String: to avoid the extra \0 at the end.
NSString* newStr = [NSString stringWithUTF8String:[theData bytes]];

tsbob

    NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
    [dateFormat setDateFormat:@"yyyy-MM"];
    NSDate *date = [dateFormat dateFromString:@"2012-4"];

//1、字符串转换为日期

　　NSDateFormatter* dateFormat = [[NSDateFormatter alloc] init];//实例化一个NSDateFormatter对象
[dateFormat setDateFormat:@"yyyy-MM-dd HH:mm:ss"];//设定时间格式,这里可以设置成自己需要的格式
NSDate *date =[dateFormat dateFromString:@"1980-01-01 00:00:01"];

tsbob

#define OC(str) [NSString stringWithCString:(str) encoding:NSUTF8StringEncoding]

#ifdef DEBUG
#  define LOG(fmt, ...) do {                                            \
        NSString* file = [[NSString alloc] initWithFormat:@"%s", __FILE__]; \
        NSLog((@"%@(%d) " fmt), [file lastPathComponent], __LINE__, ##__VA_ARGS__); \
        [file release];                                                 \
    } while(0)
#  define LOG_METHOD NSLog(@"%s", __func__)
#  define LOG_CMETHOD NSLog(@"%@/%@", NSStringFromClass([self class]), NSStringFromSelector(_cmd))

tsbob

Here's what the GCD (and ARC) version looks like:
+ (id)sharedInstance
{
  static dispatch_once_t pred = 0;
  __strong static id _sharedObject = nil;
  dispatch_once(&pred, ^{
    _sharedObject = [[self alloc] init]; // or some other init method
  });
  return _sharedObject;
}

tsbob

@implementation MySharedThing

+ (id)sharedInstance
{
  DEFINE_SHARED_INSTANCE_USING_BLOCK(^{
    return [[self alloc] init];
  });
}

@end